Certain pharmaceutical products and many biological materials are temperature sensitive, in that freezing may damage the materials, and temperatures that are too high may otherwise spoil the materials. Thus, during shipment and storage of these types of materials, they must often be maintained within a particular temperature range. One common range for such materials during shipment and/or storage is 2-8° C. With materials that are not damaged by freezing, it may be desirable to freeze the materials for storage and/or during shipment. In such cases, dry ice may be used in the storage area of a storage container to provide a storage temperature around the phase change temperature of dry ice, which is −78.5° C. Such storage containers may be active or passive. For example, a refrigerator or freezer is an active storage container and typically includes a refrigeration unit to extract heat from inside the storage container to maintain the desired storage temperature. A styrofoam cooler is an example of a passive storage container that relies on thermally insulating materials to retard heat transfer through the container walls. Passive storage containers are sometimes used with ice, dry ice, or some other type of phase change material inside the container to the maintain the storage area temperature.